You've got nothing to feel guilty about mate; it's your game to play your way and although we joke around about the USAS, it is by no means invincible. In fact, since I changed away from it, I've increased my K: D ratio!
As for which AR to try, remember, they will all feel different as they are changing foregrip/ heavy barrel effects across the board. Blitz is right, they aren't altering the M416, other then the accessory tweaks
-The FAMAS is a great weapon, get the first shot in and its a guaranteed kill due to its mad ROF. Penalty is the reload time which has caught me out plenty of times (4.5 secs). Nevertheless, it is my AR of choice. Doesn't seem to be getting a nerf in the patch
- M416 is my second choice. A bit punchier then the FAMAS as close range (less bullets needed to down an enemy) but it is traded off with a slower ROF and I felt more recoil. Still, a very good weapon.
- F2000 is kind of a cross between the two above. Small clip, high ROF, quite a bit of recoil. I haven't tried it much, but it seems pretty good.
I'd say stick with the FAMAS until you have unlocked a good few sights. I found Holo to be most effective, but each to their own.
Once you have gotten used to the M416, you can try on the IAR from support as they are share similar weapon characteristics. From that you might then migrate to belt fed LMGs which are recoil beasts but have their own virtues.
@ neema_t: Hope so too, although some weapon changes feel like changes for the sake of changes...